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Agger P, Stephenson RS. Assessing Myocardial Architecture: The Challenges and Controversies. J Cardiovasc Dev Dis 2020; 7:jcdd7040047. [PMID: 33137874 PMCID: PMC7711767 DOI: 10.3390/jcdd7040047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/04/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022] Open
Abstract
In recent decades, investigators have strived to describe and quantify the orientation of the cardiac myocytes in an attempt to classify their arrangement in healthy and diseased hearts. There are, however, striking differences between the investigations from both a technical and methodological standpoint, thus limiting their comparability and impeding the drawing of appropriate physiological conclusions from the structural assessments. This review aims to elucidate these differences, and to propose guidance to establish methodological consensus in the field. The review outlines the theory behind myocyte orientation analysis, and importantly has identified pronounced differences in the definitions of otherwise widely accepted concepts of myocytic orientation. Based on the findings, recommendations are made for the future design of studies in the field of myocardial morphology. It is emphasised that projection of myocyte orientations, before quantification of their angulation, introduces considerable bias, and that angles should be assessed relative to the epicardial curvature. The transmural orientation of the cardiomyocytes should also not be neglected, as it is an important determinant of cardiac function. Finally, there is considerable disagreement in the literature as to how the orientation of myocardial aggregates should be assessed, but to do so in a mathematically meaningful way, the normal vector of the aggregate plane should be utilised.
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Affiliation(s)
- Peter Agger
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, 8220 Aarhus N, Denmark
- Department of Pediatrics, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark
- Correspondence:
| | - Robert S. Stephenson
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK;
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Koether K, Ulian CMV, Lourenço MLG, Gonçalves RS, Sudano MJ, Cruz RKS, da Silva Branchini N, Alfonso A, Chiacchio SB. The normal electrocardiograms in the conscious newborn lambs in neonatal period and its progression. BMC PHYSIOLOGY 2016; 16:1. [PMID: 26786197 PMCID: PMC4719313 DOI: 10.1186/s12899-016-0020-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 01/12/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND Veterinary cardiology, especially electrocardiography, has shown major advancements for all animal species. Consequently, the number of ovine species used as experimental animals has increased to date. Few studies have been published on ovine systematic electrocardiography, particularly with respect to lamb physiology and neonatology. This study aimed to standardize the values of normal waves, complexes, and intervals of the electrocardiogram (ECG) in clinically Bergamasca healthy neonatal lambs, used as experimental animals. Serial computerized electrocardiography was performed in 10 male and 12 female neonates on the 1st, 7th, 14th, 21st, 28th, and 35th days of age. The following parameters were analyzed: heart rate and rhythm, duration and amplitude of waves, duration of intervals, and heart electrical axis. RESULTS During the first 35 days of life, (1) the sinusal heart rhythm was predominant, (2) there was a progressive decrease in the heart rate and R and T wave amplitude, and (3) a progressive increase in the PR, QT, and RR intervals. Finally, we confirmed that various components of neonatal evolution were more discernible in the augmented unipolar leads (aVF), which we recommend should be preferentially used in future studies. No significant statistical alterations were observed between males and females in relation to the analyzed parameters. CONCLUSIONS The information assimilated in this study is anticipated to enhance the diagnosis of multiple congenital heart defects in Bergamasca lambs and could be implemented in studies that use ovine species as experimental models.
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Affiliation(s)
- Karoline Koether
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | - Carla Maria Vela Ulian
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | - Maria Lucia Gomes Lourenço
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | | | - Mateus José Sudano
- Laboratory of Genetics and Animal Breeding, Federal University of Pampa, 97508-000, Uruguaiana, RS, Brazil.
| | - Raíssa Karolliny Salgueiro Cruz
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | - Naiana da Silva Branchini
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | - Angélica Alfonso
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
| | - Simone Biagio Chiacchio
- Department of Clinical Veterinary of School of Veterinary Medicine and Animal Science, State University of São Paulo, (UNESP), 18619-970, Botucatu, São Paulo, Brazil.
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Optimization of catheter ablation of atrial fibrillation: insights gained from clinically-derived computer models. Int J Mol Sci 2015; 16:10834-54. [PMID: 25984605 PMCID: PMC4463678 DOI: 10.3390/ijms160510834] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/03/2015] [Accepted: 05/06/2015] [Indexed: 12/04/2022] Open
Abstract
Atrial fibrillation (AF) is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA) is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation.
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Butters TD, Castro SJ, Lowe T, Zhang Y, Lei M, Withers PJ, Zhang H. Optimal iodine staining of cardiac tissue for X-ray computed tomography. PLoS One 2014; 9:e105552. [PMID: 25170844 PMCID: PMC4149378 DOI: 10.1371/journal.pone.0105552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 07/22/2014] [Indexed: 02/02/2023] Open
Abstract
X-ray computed tomography (XCT) has been shown to be an effective imaging technique for a variety of materials. Due to the relatively low differential attenuation of X-rays in biological tissue, a high density contrast agent is often required to obtain optimal contrast. The contrast agent, iodine potassium iodide (), has been used in several biological studies to augment the use of XCT scanning. Recently was used in XCT scans of animal hearts to study cardiac structure and to generate 3D anatomical computer models. However, to date there has been no thorough study into the optimal use of as a contrast agent in cardiac muscle with respect to the staining times required, which has been shown to impact significantly upon the quality of results. In this study we address this issue by systematically scanning samples at various stages of the staining process. To achieve this, mouse hearts were stained for up to 58 hours and scanned at regular intervals of 6–7 hours throughout this process. Optimal staining was found to depend upon the thickness of the tissue; a simple empirical exponential relationship was derived to allow calculation of the required staining time for cardiac samples of an arbitrary size.
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Affiliation(s)
- Timothy D. Butters
- School of Physics and Astronomy, The University of Manchester, Manchester, Greater Manchester, United Kingdom
| | - Simon J. Castro
- School of Physics and Astronomy, The University of Manchester, Manchester, Greater Manchester, United Kingdom
| | - Tristan Lowe
- School of Materials Science, The University of Manchester, Manchester, Greater Manchester, United Kingdom
| | - Yanmin Zhang
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, Greater Manchester, United Kingdom
- Department of Pharmacology, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Ming Lei
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, Greater Manchester, United Kingdom
- Department of Pharmacology, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Philip J. Withers
- School of Materials Science, The University of Manchester, Manchester, Greater Manchester, United Kingdom
| | - Henggui Zhang
- School of Physics and Astronomy, The University of Manchester, Manchester, Greater Manchester, United Kingdom
- * E-mail:
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Aslanidi OV, Nikolaidou T, Zhao J, Smaill BH, Gilbert SH, Holden AV, Lowe T, Withers PJ, Stephenson RS, Jarvis JC, Hancox JC, Boyett MR, Zhang H. Application of micro-computed tomography with iodine staining to cardiac imaging, segmentation, and computational model development. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:8-17. [PMID: 22829390 PMCID: PMC3493467 DOI: 10.1109/tmi.2012.2209183] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Micro-computed tomography (micro-CT) has been widely used to generate high-resolution 3-D tissue images from small animals nondestructively, especially for mineralized skeletal tissues. However, its application to the analysis of soft cardiovascular tissues has been limited by poor inter-tissue contrast. Recent ex vivo studies have shown that contrast between muscular and connective tissue in micro-CT images can be enhanced by staining with iodine. In the present study, we apply this novel technique for imaging of cardiovascular structures in canine hearts. We optimize the method to obtain high-resolution X-ray micro-CT images of the canine atria and its distinctive regions-including the Bachmann's bundle, atrioventricular node, pulmonary arteries and veins-with clear inter-tissue contrast. The imaging results are used to reconstruct and segment the detailed 3-D geometry of the atria. Structure tensor analysis shows that the arrangement of atrial fibers can also be characterized using the enhanced micro-CT images, as iodine preferentially accumulates within the muscular fibers rather than in connective tissues. This novel technique can be particularly useful in nondestructive imaging of 3-D cardiac architectures from large animals and humans, due to the combination of relatively high speed ( ~ 1 h/per scan of the large canine heart) and high voxel resolution (36 μm) provided. In summary, contrast micro-CT facilitates fast and nondestructive imaging and segmenting of detailed 3-D cardiovascular geometries, as well as measuring fiber orientation, which are crucial in constructing biophysically detailed computational cardiac models.
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Affiliation(s)
- Oleg V Aslanidi
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.
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